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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

'Dandelion chips' (1 Viewer)

@Remirath - Was this a chip that you installed yourself? The mechanical tolerances are quite close, there may just have been too tight a fit to the camera body? I've had that problem myself.

@tbc - There is a setting on the chip that will only allow it to fire when focus is confirmed, though I can't remember offhand exactly how to toggle it through the chip's archaic programming interface. You can also adjust for front/back focus (in rather coarse increments, though, as far as I can tell). I have no idea why the contrast should be reduced, though, I can't see any way the chip should affect the optical qualities of the lens except through some kind of internal light scattering.
 
@Remirath - Was this a chip that you installed yourself? The mechanical tolerances are quite close, there may just have been too tight a fit to the camera body? I've had that problem myself.

@tbc - There is a setting on the chip that will only allow it to fire when focus is confirmed, though I can't remember offhand exactly how to toggle it through the chip's archaic programming interface. You can also adjust for front/back focus (in rather coarse increments, though, as far as I can tell). I have no idea why the contrast should be reduced, though, I can't see any way the chip should affect the optical qualities of the lens except through some kind of internal light scattering.

Aegea,

I tried to enter program mode as instructed but the camera couldn't give me the 5sec shutter speed and the seller suggested to reset the camera to default and the programming went as planned. After that I tried to adjust the settings back to where I started with as best I could remember. When I shoot in the field and view on my computer, that's when I realized the shutter went off without "actual focus". The focus light and beep still came on before the shutter fired during manual adjustment of the focus knob.

Is there any other method to test for front / back focus? I have tried to shoot at a ruler placed 45 deg horizontal as well as vertical but not very conclusive as far as my eyes can tell or maybe I am not doing it correctly.

tbc
 
Hi tbc and Aegea

Are we talking about the proper "Dandelion" (Russian made) or the cheaper China ones?

There appears to be some differences between the programming instructions for the two.

The PELENG site at: seems to have the "proper" instructions for the Russian version.

I think Big-Is on flebay has the installation/programming instructions on the Chinese version. Please publish your experience/findings as I have just ordered some from Singapore and may need all the help I CAN GET.

Regards

Jaco
 
tbc,

Just shooting a ruler at 45 degrees is not very reliable, because you can't be sure exactly where the af sensor locked on. A specific focus test chart is better - here are three references that provide examples, they're all pretty much the same, having a bar to focus on which is separate from the scale:

http://regex.info/blog/photo-tech/focus-chart
http://www.focustestchart.com/chart.html
http://www.leongoodman.com/d70focusnew.html

Hope this helps.


Thanks Aegea for the informative links. I will try to read them over the weekends. As for the programming link you attached I am not quite sure what it meant, able to confirm if this is for adjustment of front & rear focus?

Confirmation dot justification

You can move autofocus confirmation dot slightly forward or backward by experimentally moving justification constant. One shot at aperture value 10 moves the dot back. Aperture 20 moves the dot forward. The range consists of 17 positions. On default 9 (middle position) is used. Move the confirmation dot forward or backward and try to adjust sharpness. The best justification distance is 3-5 meters.

tbc
 
tbc,

Yes, that procedure allows adjustment to correct for back- or front-focussing. I found that it works as advertised, but the adjustment is coarse - a one-shot adjustment moves the focus point rather a long way. I think all of my adjustments have been either +1, 0, or -1.

John
 
Hi tbc and John

My scope has finally arrived and I have had a few opportunities to use it. My biggest problem is that there are a few "arc seconds" of turn on the focussing knob where the image appears to be in focus in the view finder, but subsequent analysis in DPP proves that the image is way out of focus.

Maybe it is buyer's remorse due to lack of proper research, but I am beginning to question my decision to buy the chip (with reference to your remarks above).

Is the chip (or the adapter) actually worth the effort and expense? or has anyone used it with positive results?

"Live View" works well, but is a bummer to use in most situations.

Do I commit Hara Kiri or Chop Suey?

Regards

Jaco
 
Jaco,

Have you tried the focus adjustment process? It works fine with the chips I have, except, as I said, the adjustment is quite coarse. A change of + or -1 makes a significant difference in focus point.

I've found the chips worth using both for exposure and focus. In good light, the "green dot" focuses better than I can through the viewfinder. In dim light, or with a teleconverter it doesn't work at all.

John
 
Hi tbc and John

My scope has finally arrived and I have had a few opportunities to use it. My biggest problem is that there are a few "arc seconds" of turn on the focussing knob where the image appears to be in focus in the view finder, but subsequent analysis in DPP proves that the image is way out of focus.

Maybe it is buyer's remorse due to lack of proper research, but I am beginning to question my decision to buy the chip (with reference to your remarks above).

Is the chip (or the adapter) actually worth the effort and expense? or has anyone used it with positive results?

"Live View" works well, but is a bummer to use in most situations.

Do I commit Hara Kiri or Chop Suey?

Regards

Jaco


Jaco,

Did you buy the chip and DIY sticking it yourself? I have solved my problem through trial and error by sticking the chip offset from original position to about 1.5 to 2 mm. I'll be doing more testing over this weekend. So far this chip has greatly gave me more keepers except when there's camera shake or mirror slap due to poor light and slow shutter speed.

Let me know if I can be any help.


Aegea,
Meantime I need help from you to analyze my front / back focus issues. Will post pic of the chart taken soon.

tbc
 
Jaco,

Have you tried the focus adjustment process? It works fine with the chips I have, except, as I said, the adjustment is quite coarse. A change of + or -1 makes a significant difference in focus point.

I've found the chips worth using both for exposure and focus. In good light, the "green dot" focuses better than I can through the viewfinder. In dim light, or with a teleconverter it doesn't work at all.

John

Hello Aegea

I only received the chips today, so no, I have not gone through the install/adjustment process yet. I first need/want to to sort out the scope/camera combination in prime focus mode - I have done a quick and dirty focus test with a ruler and determined that I have about a 5cm front focus problem. I need to ascertain that this is indeed the problem, hence a more "scientific testing procedure" is required before I venture into chip territory.

Thank you for the feedback on the Chip/AF/Metering situation. My 60D is OK for exposure, so it is really only the focusing issue that is a bit of a bother right now. I believe that if you dial in an aperture smaller than f/8 when programming the chip, the focus confirm takes a nose dive as f/8 is the limiting aperture for most cameras. Have you tried programming it to eg. f/6 (even when using a TC) to see if it will work? Granted, the EXIF will be all cockeyed, but at least you may have focus confirmation.

Regards

Jaco
 
Jaco,

Did you buy the chip and DIY sticking it yourself? I have solved my problem through trial and error by sticking the chip offset from original position to about 1.5 to 2 mm. I'll be doing more testing over this weekend. So far this chip has greatly gave me more keepers except when there's camera shake or mirror slap due to poor light and slow shutter speed.

Let me know if I can be any help.

tbc

Hello tbc

Thank you for your kind offer and the positive feedback regarding the chip. I do appreciate it. Mine arrived today but I first want to sort out the problem with prime focus (see my writ to Aegea). Hopefully it will not be too difficult and once the matter is resolved we can continue from there.

Looking forward to the results of your testing.

Best regards

Jaco
 
Hello Aegea

.... My 60D is OK for exposure, so it is really only the focusing issue that is a bit of a bother right now. I believe that if you dial in an aperture smaller than f/8 when programming the chip, the focus confirm takes a nose dive as f/8 is the limiting aperture for most cameras. Have you tried programming it to eg. f/6 (even when using a TC) to see if it will work? Granted, the EXIF will be all cockeyed, but at least you may have focus confirmation.
Jaco,

Nikons will try to focus (or indicate when focus is achieved) irrespective of the indicated aperture, though it gets erratic below f/8 or so simply because there's not enough light for the camera to detect focus. I believe Canon will not try to focus below f/5.6 - but I'm not a Canon user so I may be wrong.

John
 
I have come up with a way of installing Dandelion chips into AF extension tubes that has more firm fixing and support. You need some AF tubes but these are mainly sold in sets of three. You can use any of the tubes, the method is the same. Also using this method you can mark the positions for the chip using the original pass through contacts. The chips are exactly the same thickness as the contact block so they will go in the right amount of protrusion.

I would suggest these tubes as they are the ones I have used.
 

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thornlv,

That's very kind of you to post some DIY shots. Really appreciate if you can post the steps between 3rd & 4th photos when you removed the original contact and how you stick the Dandelion on. Also the final assembly on the scope. Thanks a lot in advance.

I also discovered when I turn the focuser outwards to achieve focus confirm while depressing the shutter, the shots are sharper and "more in focus" as compared to achieving AF confirm while turning the focuser inwards although the shutter do fire off either way.

I have tried several times using remote and same settings to avoid variables. I have also ensured there is no free play on the focuser travel. So far I have no explanations except possible accuracy / tolerance of the camera body or dandelion chip.

tbc.
 
Jaco,

Nikons will try to focus (or indicate when focus is achieved) irrespective of the indicated aperture, though it gets erratic below f/8 or so simply because there's not enough light for the camera to detect focus. I believe Canon will not try to focus below f/5.6 - but I'm not a Canon user so I may be wrong.

John
Hi Aegea

Thank you for the input. You are correct on the Canon focus issue at apertures smaller than f/5.6. You do have metering but no focus confirmation (except for the 1D series that will AF at f/8 and, I presume, provide focus confirmation to boot).

I am still trying to do the manual focus thing without the chips and have had some success. The best way is to "rock" the focuser to and fro between the two out of focus points (near and far) and stop where the image appears sharpest in the view finder. For me, this works OK for distances up to about 50m, depending on the size of the subject. I think it is also a matter of training ones eye/hand coordination to see and feel when the image pops into focus - the more you practice the easier it may get. I have tried shots at longer distances (up to about 120m) but the results are very poor. Also, I find it very difficult at short distances (7-12m) due to the shallow DoF. Many photos have the wing or chest in focus, but the head out of focus.

This is a whole new ball game.

Regards

Jaco
 
thornlv,

That's very kind of you to post some DIY shots. Really appreciate if you can post the steps between 3rd & 4th photos when you removed the original contact and how you stick the Dandelion on. Also the final assembly on the scope. Thanks a lot in advance.

I also discovered when I turn the focuser outwards to achieve focus confirm while depressing the shutter, the shots are sharper and "more in focus" as compared to achieving AF confirm while turning the focuser inwards although the shutter do fire off either way.

I have tried several times using remote and same settings to avoid variables. I have also ensured there is no free play on the focuser travel. So far I have no explanations except possible accuracy / tolerance of the camera body or dandelion chip.

tbc.
Hi tbc

In my quest to find an easy, sure fire, fail safe manual focus method I have come across quite a few forums where this phenomenon cropped up during discussions on manual focus problems. I do not think you have to fret on this as I can't remember reading of a suitable solution to the problem anywhere.

In my reply to Aegea, above, I describe a method to manual focus. Try this with your focus confirm chip and see how it works.

Best of luck

Jaco
 
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